1. Field of the Invention
The present invention relates to process for casting slip into ceramic products such as sanitaryware, water tanks, tiles, porcelain plates and pipes, gravestones or the like.
2. Description of the Prior Art
In the prior art slip casting process, slip is introduced under a pressure in the range of 3 to 20 kg/cm.sup.2 into a pressure-resisting porous casting mold so that the water content of the slip may be extruded under the action of that pressure through the interface between the inner molding surface of the mold and the slip, via the thickness of the porous mold and eventually to the outside of the mold. This casting operation is continued until the slip in the region of the molding surface is dehydrated to deposit into a layer of a predetermined thickness. On attaining the predetermined thickness of the cast slip layer on the interior surface of the casting mold, the casting mold is rotated or inclined while being fed with compressed air (under a pressure within the range of about 1 to 2 kg/cm.sup.2) for forcibly discharging the residual slip out of the mold via a slip discharge port in the mold. After this discharging, the discharge port is closed, and additional compressed air is fed into the mold to provide further dehydration or reduction in the water content of the slip cast layer.
The main disadvantage of the prior slip casting techniques is that the casting mold requires high pressure resistance sufficient to withstand the relatively high pressure under which the slip is being introduced thereinto, which can result in costly and time-consuming production of the casting mold.
Furthermore, the casting installation as well must be durable and heavy, which would degrade its profitability.